Standard trailer hitches include a socket on the tongue of a trailer which connects to a ball mounted on the towing vehicle. The driver must back the vehicle until the trailer hitch socket is directly above the ball. Since the driver cannot see the ball and socket while driving, backing up correctly so that the ball and socket are in alignment is a difficult trial and error procedure.
Many devices have been postulated to assist the driver in this endeavor. Most consist of fairly simple mechanical visual aids. Others include electronic displays, transmitters and receivers, or camera based systems that indicate the relative alignment of the hitch ball and socket. A few claim to give the driver steering information. Many of these different techniques are summarized in U.S. Pat. No. 7,568,716 which describes a large number of existing patents.
Unfortunately, all prior art hitching aids have a number of limitations. Many must be permanently installed on the vehicle or trailer, many are complicated or expensive, and none give high precision steering guidance to the driver or assist in backing up a hitched trailer.
Accordingly, there is a need for a simple, low cost, portable, universal, precision hitching guidance system for both hitching up a trailer and backing up a hitched trailer.